Osteoarthritis (OA) is the leading cause of pain and disability among older adults and therefore a condition of particular importance to the National Institute on Aging. Racial minorities and individuals with low socioeconomic status (SES) are at greater risk for OA, and one key factor that may underlie these disparities is exposure to occupational and household tasks that involve substantial joint loading (i.e., bending, lifting heavy objects). The overall goal of this project is to advance understanding of specific occupational risks for knee and hip OA and how these factors may mediate racial and socioeconomic disparities in the prevalence and severity of OA. This proposal is in response to NIH Program Announcement PA-06-0543, Mechanisms, Models, Measurement, and Management in Pain Research and will focus on two aspects of this PA: Epidemiology of Pain and Health Disparities. The proposed research involves a series of secondary data analyses of two large OA studies: the Johnston County Osteoarthritis Project (JoCo OA) and the Osteoarthritis Initiative (OAI). JoCo OA is one of the largest population-based prospective studies of OA, involving over 4,000 African American and Caucasian residents of Johnston County, NC. OAI is a multi-center longitudinal prospective observational study of knee OA, involving an ethnically diverse sample of approximately 4,500 individuals who have or are at risk for tibiofemoral OA. We will examine the following research questions among these two cohorts: 1. Do occupational and household activity exposures mediate associations of race and SES with hip and knee OA prevalence and radiographic severity? 2. Do current occupational and household activities mediate the association of race with joint pain severity or progression in pain severity in knee OA? 3. Are occupational and household activity exposures associated with OA incidence, and do these associations differ according to race or SES? We have outlined specific plans for seven sets of analyses related to the above research questions, and based on these findings will also conduct additional analyses in areas of importance. We plan to complete three sets of analyses in year one and four sets of analyses in year two of the award period, submitting a corresponding manuscript for each. Because osteoarthritis (OA) is a leading cause of pain and disability, affecting about half of all older adults, it is a key public health concern. This project aims to understand how occupational and household activities are related to OA and whether these risk factors explain the higher rates of OA that have been observed among racial minority groups and individuals with lower socioeconomic status. This information will ultimately be used to design programs to reduce occupational and household risks for OA among vulnerable individuals. PUBLIC HEALTH RELEVANCE: Because osteoarthritis (OA) is a leading cause of pain and disability, affecting about half of all older adults, it is a key public health concern. This project aims to understand how occupational and household activities are related to OA and whether these risk factors explain the higher rates of OA that have been observed among racial minority groups and individuals with lower socioeconomic status. This information will ultimately be used to design programs to reduce occupational and household risks for OA among vulnerable individuals.